Part 5 (1/2)

Counterweight: 6,600 sin 5435' 5,380

Power: 156 p.s.i. 2 (pistons) 1,341.5 sq. in. (piston area) ------------------------------------------ 13 (ratio) 32,196 37,576 lb.

------ ---------- Excess to overcome friction 13,856 lb.

_The Edoux System_

Negative effect

Unbalanced weight of plungers (necessary to raise full lower car and weight of cables on lower side) 42,330 lb.

Live load: 60 persons @150 lb. 9,000 ------ -- 51,330 lb.

Positive effect

Power: 227.5 p.s.i. 2 (plungers) 124 sq. in. (plunger area) 56,420 lb.

---------- Excess to overcome friction 5,090 lb.

Footnotes:

[1] Translated from Jean A. Keim, _La Tour Eiffel_, Paris, 1950.

[2] The foundation footings exerted a pressure on the earth of about 200 pounds per square foot, roughly one-sixth that of the Was.h.i.+ngton Monument, then the highest structure in the world.

[3] A type of elevator known as the ”teagle” was in use in some multistory English factories by about 1835. From its description, this elevator appears to have been primarily for the use of pa.s.sengers, but it unquestionably carried freight as well. The machine shown in figure 7 had, with the exception of a car safety, all the features of later systems driven from line shafting--counterweight, control from the car, and reversal by straight and crossed belts.

[4] The Otis safety, of which a modified form is still used, consisted essentially of a leaf wagon spring, on the car frame, kept strained by the tension of the hoisting cables. If these gave way, the spring, released, drove dogs into continuous racks on the vertical guides, holding the car or platform in place.